Mass spectrometry (MS) is an indispensable technique in food safety, forensics, pharmaceuticals development, and in the detection of hazardous substances; and its use within the biological sciences is growing exponentially. Whereas traditional MS studies began with sample homogenization, recent technological advances have enabled imaging by mass spectrometry (MSI). Mass spectrometry requires the ionization (charging) of a sample, and this talk presents methods for improving the spatial resolution for ionization that employs lasers and a chemical “matrix” (Matrix-Assisted Laser Desorption Ionization-MALDI). Two novel techniques, both of which increase spatial resolution of MALDI imaging by ~10-fold and enabled the first analysis of single mammalian cells (neurons), will be presented. The first technique involves the simultaneous chemical fixation of tissues and deposition of matrix. The second technique involves the injection of a solution of MALDI matrix only upon cells of interest. Both techniques are compatible with fluorescence microscopy. The application of these techniques to the study of a mouse model of the neurodegenerative disease, Amyotrophic Lateral Sclerosis (ALS) is presented.
DiagnosticsFood and BeverageForensic ScienceMass Spectrometry